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Pulley Moulding.

PATTERN

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MOULD

prints for the centre hole, and divided in halves by a horizontal
plane. In all other respects it is the counterpart of the casting.
The operation is as follows: referring to Fig. n, .we must first
lay the bottom half of the pattern in the bottom box, and make
the parting b b ; next put in the top half of pattern, and make the
parting / /; lastly, fill up the box, and ram well together. The
pattern has now to be drawn out, and this is done by first lifting
off top box, taking away the top half of pattern, and returning top
box. Now, on turning the whole upside down, the bottom half
of pattern becomes the top, and may be similarly released. The
ring of sand M, it will be noticed, has all this time remained
resting on that half which happened to be at the bottom. It
is only necessary to make the core as in last example, put it in